Canister lifter for breathing apparatus



Oct. 18, 1960 c. L. LEFFLER, JR

CANISTER LIFTER FOR BREATHING APPARATUS 2 Sheets-Sheet 1 Filed July 2, 1959 O R W H- m N w N A m u u L m. mm o m n u m 3 \N m i R w \w w Kw w lvlll S" 1 WMHW N mm G n k P k w w Q Q m .w\ til.

A CHHRLES 1.. LEFFLER, up.

A amdfim m H15 FWTQRNEYS c. L. LEFFLER, JR 2,956,562 CAN ISTER LIFTER FOR BREATHING APPARATUS 2 Sheets-Sheet 2 Oct. 18, 1960 Filed July 2, i959 H15 077-0 m/E -/5 CANISTER LIFTER FOR BREATHING APPARATUS Charles L. Lefller, Jr., Monroeville, Pa., assignor to Mine Safety Appliances Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed July 2, 1959, Ser. No. 824,620

2 Claims. (Cl. 128-191) This invention relates to oxygen breathing apparatus, and more particularly to apparatus for holding a removable canister and permitting it to be quickly replaced by a new one.

In Hamilton Patent 2,693,181, oxygen breathing apparatus is shown, in which a canister that has been pushed up into a guard by hand is then lifted farther by a handle pivoted at the top of the guard. When the handle is swung down, it forces the canister up into a slide valve. This is accomplished by providing the upper end of the handle with pawls that engage the bottom of a lip around the neck of the canister. In order to position the pawls beneath the neck lip, they first have to be swung down by raising the handle so that the lip can be moved up behind them. It has been found that sometimes the neck of the canister is inadvertently jammed up against the pawls before they have been lowered, or that the user starts to raise the pawls by lowering the handle prematurely before the neck lip has cleared the pawls and thereby jams them into the lip. In either case, the pawls and their supporting arms may be damaged if much force has been applied.

It is among the objects of this invention to provide oxygen breathing apparatus of the type shown in Patent 2,693,187, in which the lifting pawls cannot be raised from their lowered position until after the lip of the canister has been raised above the point where it could damage the pawls. This object is accomplished by pivotally mounting levers at the upper end of the guard in which the canister is inserted. The levers have hooks at their upper ends that engage shoulders on the lifting pawls when the latter are in their lowered position. This looks the pawls in that position. The levers extend downward at an inclination and their lower ends are engaged by the canister as the neck is being raised behind the lifting pawls. Further manual raising of the canister will therefore tilt the levers to release the hooks from the shoulders so that the lifting pawls can be raised to engage the bottom of the neck lip and thereby force the canister farther upward.

The preferred embodiment of the invention is illus trated in the accompanying drawings, in which Fig. 1 is a front view, with parts broken away, of the slide valve and canister guard and lifter, showing the canister in stand-by position;

Fig. 2 is a side view with part of the guard broken away;

Fig. 3 is a side view with the handle raised and the canister pushed up into the guard;

Fig. 4 is a fragmentary view, similar to the preceding figure, but with the canister raised still higher;

Fig. 5 is a side view, partly in section, of the apparatus in operating position; and

Fig. 6 is a plan view of the guard and horizontal section of the valve taken on the line VI-VI of Fig. 1.

Referring to the drawings, an upright sleeve-like guard 1 for an oxygen generating canister 2 is supported by a curved breast plate 3 that can be strapped against the chest of a person in any well-known manner. In actual practice, the wall of the guard is provided with a large number of holes to reduce its weight, and it may be covered with insulating material tohelp protect the wearer from the heat produced by the canister. Extending back across the top of the guard from its front to the top of the breast plate are a pair of laterally spaced metal brackets 4. that have parallel vertical flanges 5 and inwardly bent fingers 6 above the flanges. Extending through openings in the ends of these fingers are screws 7 which support between the brackets a slide valve 8 like the one shown in Patent 2,710,003, to which ref-'- erence is made for a more complete description and more detailed drawings. As shown in Figs. 1 and 6 herein, this valve has a cylindrical casing 10 provided in its top with an inlet port 11 adapted to be connected to the exhalation tube of a facepiece (not shown). The side of the casing is provided with an outlet 12 for con nection to a breathing bag (not shown). The outlet of the breathing bag is connected to one end of a tubular elbow 13 supported by a metal strip 14 from one of the brackets 4. The outlet of the elbow is adapted to be connected to the inhalation tube of the facepiece.

Inside the valve casing there is a valve seat 16 around the lower end of the inlet port. Directly below this seat there is a vertically movable sleeve valve 17 that has a flange 18 around its lower end which is pressed downward by a coil spring 19. The bottom of the flange normally seats against a lower valve seat 21, but the sleeve valve can be pushed upward into engagement with upper seat 16 by means of a skirt 22 (Fig. 5 slidably mounted in the lower part of the valve. This skirt has a flaring lower end encircled by a rubber ring 33 suspended from the casing. Extending up into the sleeve valve and projecting below the skirt is a tubular member 24 provided with a perforated point 25 for piercing the conventional seal in the neck of an oxygen generating canister when the canister is pushed up against the point. The upper end of the canister neck is provided with an encircling lip or flange 27, on which a rubber-like sealing ring 28 is mounted. As is well known, the canister is filled with a chemical that will generate oxygen when it is exposed to the moisture in the exhaled breath of the person using this apparatus.

Extending through holes in the front ends of bracket flanges 5 are hinge pins, with threaded ends 30 that serve as pivots for a U-shaped member 31 that extends forward and then curves downward for attachment to the upper end of a channel member 32. These two members form part of a handle that can be swung up to horizontal position as shown in Fig. 3. Rigidly mounted in the lower end of channel 32 is a bracket 33, as shown in Figs. 1 and 5, that has vertically spaced flanges provided with axially aligned holes. A latch 34 is slidably mounted in these holes and has a tapered upper end projecting from the upper flange. The latch is urged upwardly by an encircling coil spring 36 compressed between the lower flange and a pin 37 that extends through the latch directly below the upper flange. The 'ends of the pin also extend through an inverted U-shaped slide 38, the opposite'sides of which slide in notches in the sides of the bracket flanges. The point of the latch normally projects up behind the head of a pin 39 projecting from the front of the guard through slide 38. When it is desired to release the handle from this pin, the wearer inserts a finger through a hole 40 in the channel and presses down on the U-shaped slide in order to cause pin 37 to depress the latch.

Above the handle locking mechanism just described, there is a pin 42 extending across channel 32, with its ends mounted in the opposite sides of the channel. Pivotally mounted on this pin are parallel ears at the lower end of a lever 43, the upper end of which is urged backward away from the handle by a wire spring 44 looped around the pin and having portions pressing against the inner surfaces of the lever and channel as shown in Fig. 4. The upper end of the lever projects through an opening 46 in the front of the guard and will support a canister in stand-by position in the guard by projecting under neck flange 27, as shown in Fig. 2. When a canister is first pushed up into the guard, sealing ring 28 on top of its neck first engages the lever and swings it outward against the resistance of spring 44. As soon as the neck flange passes the lever, the latter swings back toward the neck of the canister. Upward movement of the canister at this time is limited by a stop 47 projecting through guard opening 46 from the handle above lever 43.

Also pivotally mounted on pivot pins 30 are a pair of arms 50 that are integrally connected in front of the guard by a cross bar 51. This cross bar normally rests on top of the base of U-shaped member 31 at the upper end of channel member 32, on which it is held by pins 52 extending slidably through them. The pins project a considerable distance down through member 31 and support coil springs 53 that are compressed between that member and heads on the lower ends of the pins. These springs normally hold cross bar 51 and member 31 tightly together to form a fork and complete the handle. When the handle is in its lower position, the arms extend rearwardly from pivot pins 30 to points about halfway back along the opposite sides of the slide valve, as shown in Figs. 2, and 6. Projecting from the inner surfaces of the rear ends of the arms are pawls 54 which preferably are cylindrical. As shown in Fig. 1, the pawls have large inner ends connected to the arms by necks of smaller diameter. They are so formed and positioned that the bottom of valve skirt 22 rests on the necks, and the necks hold the skirt in a slightly elevated position in which it lifts the sleeve valve 17 from lower seat 21 but does not allow the sleeve valve to engage upper seat 16. Consequently, as shown in Fig. i, as long as the canister is absent or is in stand-by position in the guard the sleeve valve is held out of engagement with both valve seats and therefore there is no chance of the valve being impaired by the continuous pressure of the sleeve valve against either seat over a long period of time.

When it is desired to use the breathing apparatus, the handle is swung forward and up to the position shown in Fig. 3, which swings pawls 54 down to the front wall of the guard. The hand is held under the canister at this time to support it, because the handle swings lever 43 away from the canister neck. With stop 47 and the pawls out of the way, the canister can be pushed upward by hand until the top of the canister engages the lowered pawls. In being moved up this far the seal in the neck of the canister is pierced by the point of tubular member 24 of the valve, and sealing ring 28 enters the lower end of the flaring valve skirt 22. The handle is then swung down again, causing the large inner ends of pawls 54 to engage the bottom of neck flange 27 of the canister and force the canister upward as shown in Fig. 5. This causes the sealing ring to engage the skirt and push the sleeve valve l7.up until it engages upper seat 16, which normally occurs while the lower end of the handle is still an inch or more away from the guard. Continued movement of the handle back toward the guard until it is locked on pin 39 will compress coil springs 53 and separate the channel 32 from arm cross bar 51. Because of this resilient connection between the channel and arms 50, the sleeve valve 17 is always resiliently pressed against the upper valve seat even though there is wear in the parts or variation in canister dimensions.

It is a feature of this invention that the lip on the canister neck cannot be jammed into the pawls as the canister is being pushed up into the guard. Such an accident is prevented by locking the handle in its raised position in such a manner that it cannot be lowered again until a canister has been pushed far enough up into the guard to release the handle. The release does not take place until the lip of the canister neck has been moved above the level of the lowered pawls. To accomplish this result, levers 56 are pivotally mounted at opposite sides of the canister neck, each lever being supported by a pin 57 mounted in a pair of tabs 58 bent down from one of the brackets 4 at the top of the guard. The pivot pins are located near the front of the guard, and the levers extend down from them toward the back of the guard at an inclination of about 45, as shown in Fig. 2. A torsion spring 59 is coiled around each pin and has one end pressing up against the overlying bracket and the other end pressing down against the lever. The levers are of such length that their lower ends will not be engaged by the top of the canister at the base of the neck until the lip of the neck has been moved up past the lifting pawls, as shown in Fig. 3.

The levers project up through slots 60 in brackets 4 and have rearwardly facing hooks 61 at their upper ends. When the handle is in its upper positon shown in Fig. 3, these hooks engage shoulders formed on the handle fork by bending ears 62 outward from the rear end of U-shaped member 31. When the handle is down against the guard, the ears are horizontal as shown in Figs. 1 and 2, but when the handle is raised, the ears are swung around to vertical position in back of the hooks which then latch onto them. That prevents the handle from being lowered again. A canister in the guard then is pushed up higher and engages the lower ends of the levers as shown in Fig. 3. Further upward movement of the canister tilts the levers and swings the hooks away from shoulders 62 as shown in Fig. 4. That unlocks the handle so that it can be lowered to swing the pawls back up against the lip of the canister neck and thereby raise the canister still higher to operative position, which is illustrated in Fig. 5. It will be seen that with this construction the handle cannot be swung down accidentally or prematurely while the canister is being raised in the guard, thereby preventing the possibility of damaging the canister or the apparatus holding it.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, i desire to have it. understood that, within the scope of the appended claims, the invention may be practiced otherwise than as spe cifically illustrated and described.

I claim:

1. In oxygen breathing apparatus, a hollow guard, a vertically movable oxygen generating canister removably disposed in said guard and having a neck with an enlarged upper end, supporting means mounted on the upper end of the guard, an upright handle in front of the guard having a fork at its upper end extending back-- ward above the canister, means pivotally connecting the upper portion of the handle to said supporting means near the front of the guard, the lower end of the handle being adapted to be swung upward to swing the fork downward before the neck of the canister is raised manually behind the fork, means on the rear end of the fork for engaging the bottom of the raised upper end of the canister neck to lift the canister when the handle is swung down again, and pivotally mounted levers at the upper end of the guard having hooks at their upper ends,

said fork being provided with shoulders engaged by said hooks when the fork is in its lowered position to lock it there, the levers extending downward at an inclination and adapted to be engaged by the top of the canister at the base of its neck as the neck is being raised behind said lifting means, whereby further manual raising of the canister will tilt the levers to release said hooks from said shoulders.

2. In oxygen breathing apparatus according to claim 1,

said hooks projecting above said supporting means near the front of the guard and facing rearwardly, and said shoulders being located at the back of the books when said fork is in its lowered position.

References Cited in the file of this patent UNITED STATES PATENTS 2,693,181 Hamilton Nov. 2, 1954 

